In the production of frozen comestibles, such as ice cream, a liquid composition including a fat component, a sugar component, a water component, and other flavouring agents are mixed together. The temperature of the composition is then reduced to about −5° C. to −8° C. while the mixing continues. Once temperature of the composition has been reduced, it is placed into vessels for shaping and further freezing until the composition substantially solidifies.
In order to obtain the correct consistency, the amount of freezing required is dependent on the amount of sugar, fat and other ingredients in the composition. The liquid composition therefore is imparted with a “freeze point depression” as a result of the various ingredients affecting the freezing point of the composition. The imparted freeze point depression can be characterized in terms of the sucrose equivalency of the liquid composition. The sucrose equivalency of a given liquid composition may include the contribution of the components of the composition, such as milk solids or glucose components and other ingredients included in the liquid composition. The sucrose equivalency is a measurement known in the industry and is used to compare the freezing capacity of a composition to the freezing rates and temperature of various concentrations of sucrose so as to provide a standard against which to measure the freeze point depression. For example, for a given ingredient in solution, the equivalent concentration of sucrose that would have the same freezing point depression effect can be calculated. Thus, the sucrose equivalency allows the freezing point depression effect caused by a particular ingredient in the composition to be calculated.
In order to calculate the sucrose equivalency, and the thus the freezing point depression effect of a given ingredient, the molecular weight of the components of an ingredient which can dissociate in water are determined Thus, the molecular weight of each dissociated component as it exists in water is determined The percentage of dissociated component relative the total molecular mass of the ingredient, including the stoichiometric ratio of water required for dissociation is determined. Separately, the molecular weight of sucrose is then divided by the molecular mass of the dissociated component and multiplied by 100 to arrive at the sucrose equivalent for each dissociated component. To calculate the freezing point depression resultant from the ingredient, the percentage of dissociated component relative the total molecular mass of the ingredient is divided by 100 and multiplied by the sucrose equivalent for each component and the sucrose equivalents are summed Therefore, according to the calculations, for every 100 g of the given ingredient in a given volume of water, the freezing point of the water including the ingredient, would be depressed by the amount in grams of sucrose in water equal to the summed sucrose equivalent value. For example, the sucrose equivalency, where sucrose is taken to be “1”, non-fat milk solids have a sucrose equivalency of 0.545, and high fructose corn syrup has a sucrose equivalency of 1.8.
Therefore, when producing many frozen comestibles, such a calculation can be used to determine the sucrose equivalency of the ingredients and thus, the freezing point depression such that a substantially uniform frozen comestible results. For example, the ratios of the various ingredients can be adjusted such that the amount of each ingredient results in a substantially consistent freezing point for all the ingredients. However, if an ingredient is added to the liquid composition that has a much higher sucrose equivalency or significantly lower freezing point than the other ingredients, adjustment of the ingredient ratios may not be possible to obtain the desired frozen comestible and the resultant frozen comestible does have a substantially uniform, or smooth, consistency since the water component freezes well before the other ingredients.
Furthermore, some ingredients, such as alcohol have a non-linear sucrose equivalency with increasing concentrations in a given fluid medium. Alcohol (ethanol), for example has a geometrically progressive effect on freezing point depression, wherein, for example, a 2.5% concentration equates to a sucrose equivalency of 17, and a 17.5% concentration equates to a sucrose equivalency of 126. The result of freezing liquid compositions also containing alcohol, under conditions known in the art to produce frozen comestibles, is undesirable as ice crystal agglomerations or ice crystal striations or “pockets” of ice crystals are formed in the frozen comestible. Also, with some desirable ingredients, the ratios cannot be adjusted so as to obtain the desired uniform consistency of the frozen comestible while maintaining the desired flavor and other properties of the frozen comestible. As noted above, such pockets of ice crystals are found when freezing liquid compositions that include an alcohol component using known techniques for making a frozen comestible. Therefore, it would desirable to develop a process for freezing compositions that include an alcohol component in which the resulting frozen composition is substantially devoid of ice crystal striations or pockets and has an ice cream-like consistency at a serving temperature. Furthermore, it would be desirable to provide a process for producing a stable frozen alcohol-containing comestible which can be stored and served at product temperatures normally associated with conventional ice creams.